1. Technical Field
Embodiments of the present disclosure generally relate to semiconductor integrated circuits and, more particularly, to internal voltage generation circuits.
2. Related Art
In general, semiconductor memory devices receive a power supply voltage VDD and a ground voltage VSS from an external system to generate internal voltages used in operations of internal circuits constituting each semiconductor memory device. The internal voltages for operating the internal circuits of the semiconductor memory devices may include a core voltage VCORE supplied to memory core regions, a high voltage VPP used to drive or overdrive word lines, and a back-bias voltage VBB applied to a bulk region (or a substrate) of NMOS transistors in the memory core region.
The core voltage VCORE may be a positive voltage which is lower than the power supply voltage VDD supplied from the external system. Thus, the core voltage VCORE may be generated by lowering the power supply voltage VDD to a certain level. In contrast, the high voltage VPP may be higher than the power supply voltage VDD, and the back-bias voltage VBB may be a negative voltage which is lower than the ground voltage VSS. Thus, charge pump circuits may be required to generate the high voltage VPP and the back-bias voltage VBB.